I posted on here a couple of months ago about my trouble with soot on the transom after a run out on the water in my '06 Tahoe w/Mercruiser 135 HP, 3.0 L Alpha One. I'm still having the trouble, but have made an interesting observation that someone here might be able to help me out with.
It seems that the soot is only accumulating during the very beginning of our lake run each time. The last few times, we've run it about 15 minutes, then dropped anchor in a cove for a swim -- and to take a sponge to clean off the soot. Then, we can run all over the lake the remainder of the day and no more soot whatsoever! So it appears that the soot accumulates when the engine is cold -- or at least, just getting started.
Also, when I start it up cold, I do notice a different sound coming from the engine when idling and at low speed. Sounds kinda like a hissing noise ... kinda like someone blowing water through a straw, or something like that. It lasts for about 10 minutes -- while idling through the no-wake zone near the launch ramp, then seems to go away after I can go full-throttle for a bit. I definitely don't hear the same sound when idling out on the water or slow speed coming back through the no-wake zone after a lake run. Again, just at the beginning after starting the engine.
I'm wondering if these two are related? I'm planning to have a guy do a tune-up on it next week, but wanted to try to tap the wisdom of this group to see if there's some "tell-tale" sign that's happening that I can steer him to. As a new boater, I'm at a loss to explain it.
Any insight would be greatly appreciated! THANKS!
- Mark
It seems that the soot is only accumulating during the very beginning of our lake run each time. The last few times, we've run it about 15 minutes, then dropped anchor in a cove for a swim -- and to take a sponge to clean off the soot. Then, we can run all over the lake the remainder of the day and no more soot whatsoever! So it appears that the soot accumulates when the engine is cold -- or at least, just getting started.
Also, when I start it up cold, I do notice a different sound coming from the engine when idling and at low speed. Sounds kinda like a hissing noise ... kinda like someone blowing water through a straw, or something like that. It lasts for about 10 minutes -- while idling through the no-wake zone near the launch ramp, then seems to go away after I can go full-throttle for a bit. I definitely don't hear the same sound when idling out on the water or slow speed coming back through the no-wake zone after a lake run. Again, just at the beginning after starting the engine.
I'm wondering if these two are related? I'm planning to have a guy do a tune-up on it next week, but wanted to try to tap the wisdom of this group to see if there's some "tell-tale" sign that's happening that I can steer him to. As a new boater, I'm at a loss to explain it.
Any insight would be greatly appreciated! THANKS!
- Mark